Christopher ate 2 slices of cake. Emily ate 4 slices. If Christopher ate $\dfrac{2}{11}$ of the cake, what fraction of the cake is remaining?
Explanation: If 2 slices represent $\dfrac{2}{11}$ of the cake, there must have been a total of 11 slices. $\text{fraction of cake remaining} = \dfrac{\text{number of slices remaining}}{\text{number of slices total}}$ Together they ate 6 slices, which leaves 5 out of 11 slices remaining. There is $\dfrac{5}{11}$ of the cake remaining.